#include <iostream>
#include <vector>
#include <string>

using namespace std;

int main() {
    string a;
    cin >> a;
    vector<char> l(a.begin(), a.end());
    bool t = true;
    for (size_t i = 0; i < l.size() - 1; ++i) {
        for (size_t j = i + 1; j < l.size(); ++j) {
            if (static_cast<int>(l[i]) == static_cast<int>(l[j]) + 1 || static_cast<int>(l[i]) == static_cast<int>(l[j]) + 2) {
                continue;
            } else {
                t = false;
            }
        }
    }
    if (t == true) {
        cout << "True" << endl;
    } else {
        cout << "False" << endl;
    }
    return 0;
}
